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UNITED STATES PATENT OFFICEQ SIMON H. MIX, OF SCHOHARIE, NEW YORK.

PROCESS FOR MAKING STEREOTYP E-PLATES.

Specification forming part of Letters Patent No. 29,091, (la-ted July 10, 1860.

To all whom it may concern:

Be it known that I, SIMON H. MIX, of Schoharie, Schoharie county. State of New York, have invented a new and useful Improvement in the Process of Making Stereotype-Plates; and I do hereby declare the following to be a full and exact description of my said improvement without drawings, the same being unnecessary to the full description, audthe said improvement not being of a nature to beillustrated by drawings.

The nature of my invention consists in interposing between the type-form (when set up to receive the plaster-of-paris as a matrix) and the plaster-of-paris or other material for the matrix a very thin sheet of tin or other soft-metal foil, and pressing the same into and upon the types and form, so as to receive the exact impression thereof, and then placing thereon the material to form the matrix, the foil thus used to be left on the plaster-of-paris mold when immersed in the bath of type-metal, or to be stripped off before immersion, as may suit the operator.

The manner of using and applying my said improvement is as follows: The type are first set up in the form for the required page, sheet, or card, as is usual and well known, in preparing for obtaining the desired stereotypeplate. Over this form of type I place an exceedingly thin foil in one or more pieces. This foil I prefer to have of tin, as being a very soft metal, easily rolled into sheets, and as melting at a temperature considerably below the melting-point of the lead used in making stereotype-plates but other metals may be used for the foil, and 1 do not mean to confine myself to the use of tin, but consider it as upon the whole the best for the purpose. This foil must then be pressed down upon the face of the type by the pressure of some soft substance held in the hand or under a press-such as rubber or felt-so that the foil will receive the exact impression of the face of the type, and be sunk also into the spaces or recesses below the face of the type without breaking the foil, if possible. IVhen this has been done, the plaster-of-paris in asoft state is applied to the type-form directly upon the foil in the usual manner. When the plaster (or other material used) has set or hardened, the foil will usually rise or come off the type-form with it, and the matrix thus formed may be either immersed in the melted type-metal with or without the foil upon it. immersed in the bath of melted metal, it melts, if of tin, instantly from the lower temperature of the melting-point of tin than that of lead, and thereby coats or plates the stereotypeplate cast thereon with asmooth uniform coating of tin. The foil may, however, if desired, be stripped from the matrix after it has received the impression and set or hardened, and the matrix or mold receive the melted lead directly upon its face in the usual manner; but in either case the stereotypeplate so cast will be found to be more distinct, smooth, and,perfect than has otherwise been attainable, and will not require the usual labor of going over and taking out defects and preparing for being used in printing.

Having thus described my improvement and the manner of applying and using the same, what I claim as my invention is The use of foil of ti n or other metal upon the face of the type-form to be stereotyped,and interposed between it and the matrix or mold for the stereotype-plate, in the manner and for the purposes described.

SIMON H. MIX.

Where the foil is 

